Note: Descriptions are shown in the official language in which they were submitted.
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TAPE ROLL LINER/TAB, APPLICATION APPARATUS AND METHOD
BACKGROUND OF THE INVENTION
The invention relates to a process and apparatus for forming coreless rolls of
pressure sensitive adhesive tape.
There are many known methods and apparatus for forming individual spools or
rolls of web material. The web material is often supplied in bulk in roll
form, which is then
unrolled, slit longitudinally and wound into individual strips of web material
about a
plurality of pre-aligned cores of cardboard or plastic. In the case of
pressure sensitive
adhesive tape, for example, typical cores are formed of paper, cardboard or
plastic.
Because it is useful to provide such tape in different widths, an inventory of
cores of
different widths is thus also required. The winding of tape onto a core
necessitates
additional material handling (e.g., core loading) during the tape roll
production process. In
addition, it is imperative during tape roll production that there be no
misalignment between
the core and the advancing strip of web material during winding.
Ivlisalignment can cause
tape telescoping during winding or an axial offset winding of the tape onto
the core ("off
core" winding), both of which can lead to product aesthetic issues and
dispensing
difficulties.
The use of a core presents additional material inventory scheduling and
storage
requirements, and results in extra shipping weight and volume for the tape
roll product. In
addition, the cost of the core itself, particularly for shorter length tape
rolls, can represent a
significant proportion of the product's cost. Further, the disposal of the
core may present
waste and environmental concerns when the supply of tape from the core has
been
depleted. Even if the core is formed from a material or composite that is
recyclable, its use
requires additional handling by the user in order to be salvaged for reuse or
reprocessing.
Under certain conditions over time (e.g., variable humidity and temperature),
the
discontinuity between the different core and wound tape materials can cause
deformations
to occur in the tape rolls, such as rippling or bulging, which are
aesthetically undesirable.
Coreless rolls of pressure sensitive adhesive tape have been developed, along
with
processes for winding such rolls. One such process is disclosed in Hall et al.
U.S. Patents
Nos. 3,770,542 and 3,899,075. A diametrically expandable and retractable
mandrel is used
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for winding pressure sensitive adhesive tape thereon. Tape winding is
initiated on this
mandrel by leaving exposed a short segment of adhesive at the leading end of
the tape. A
next segment of the adhesive on the tape is covered with a baclcing sheet
which presents a non adhesive surface to the mandrel for the remainder of the
innermost wrap of tape about
the mandrel. After a desired length of tape has been wound into a roll on this
mandrel (in
its expanded state), the tape is cut, winding stopped and the mandrel
diametrically
retracted. Rotation in an opposite relative direction between the mandrel and
the tape then
folds back the short adhesive bearing leading edge segment onto the backing
sheet, thereby
leaving no adhesive exposed on the innermost wrap of the tape roll. While this
process
results in a coreless roll of pressure sensitive adhesive tape, it is
necessary to periodically
stop the advance of web material through the apparatus for indexing purposes
during tape
roll production, thereby inhibiting high speed and continuous manufacturing of
a coreless
tape product. In addition, the further processing on the tape roll (rotation
reversal of the
mandrel relative to the roll) is necessary in order to fully achieve an
innermost wrap ofthe
tape roll which is free of adhesive. As mentioned, this process also requires
a mandrel
which expands and contracts diametrically. A pneumatically expandable mandrel
is
disclosed, which, of course, requires pneumatic couplings and presents a more
complex and
expensive mandrel arrangement than desired.
SUMM.ARY OF THE INVENTION
The present invention includes a method of sequentially forming a plurality of
coreless rolls of pressure sensitive adhesive tape, and apparatus therefore.
The inventive
method includes providing a first rotating winding mandrel in a first winding
station,
directing a leading edge of an advancing strip of pressure sensitive adhesive
tape around
and directly against the first mandrel, and winding the tape successively upon
itself and the
first mandrel to form an in process coreless tape roll. The first mandrel and
in process
coreless tape roll are advanced to a second transfer station while advancing a
second
rotating mandrel into the first winding station for engagement with the
advancing tape. The
tape is severed between the first and second mandrels to define a trailing
edge with the tape
wound upon the first mandrel and the tape is then wound on the first mandrel
in the second
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transfer station until the trailing edge is also wound thereon to form a
completed coreless
tape roll on the first mandrel.
To facilitate the coreless winding of the tape on a winding mandrel, in one
embodiment the winding mandrel is rotated about a tape winding axis in a first
direction
and at a first rate. A cinch roller assembly rotates in a second, opposite
direction. A
support for the cinch roller assembly is movable relative to the winding
mandrel between a
first position spaced from the winding mandrel and a second position wherein
the cinch
roller assembly is urged into contact with the winding mandrel. When the
support is in its
second position, the cinch roller assembly is rotated at a second, faster
rate, and a leading
edge portion of an advancing strip of tape is wound about the winding mandrel.
In the
preferred embodiments, the leading edge portion of the strip of tape has a
liner sufficient to
at least mask the adhesive on an innermost wrap of tape being wound on the
winding
mandrel. In one preferred embodiment, the support also has a strand feed
roller assembly,
which rotates in the second direction, at the second faster rate, when the
support is in its
second position.
In one embodiment of the winding mandrel, it includes a cylindrical shaft
having an
axis of rotation, with at least a portion of the shaft having a
circumferential tape supporting
segment adapted for receiving tape wound thereon. The circumferential tape
supporting
segment has a tape engaging surface portion that, in a radial orientation, is
compressible yet
sufficiently stifrto support the tape as it is successively wound about the
shaft to form a
tape roll, and that is sufficiently pliant to permit ready axial removal of a
wound tape roll
from the shatt.
In another embodiment, the process for sequentially forming a plurality of
coreless
tape rolls of pressure sensitive adhesive tape includes longitudinally
advancing a web having
first and second major surfaces, with one surface thereof bearing pressure
sensitive adhesive
thereon. A liner/tab is applied across a lateral width of the advancing web on
the adhesive
bearing surface thereof. The advancing web is then wound about a mandrel
member to
define a tape roll, whereby an innermost wrap of the web for each tape roll
includes an
extent of the liner/tab sufficient to mask the adhesive thereon. Preferably,
the inventive
method also includes cutting the liner/tab and web lateralIy into two
segments, with a first
segment of the liner/tab defining said extent for one tape roll, and a second
segment of the
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liner/tab defining a mask for adhesive along an outermost
end portion of a web for a previously wound tape roll.
According to one aspect of the present invention,
there is provided a method for applying a liner/tab strip
onto a transversely moving web comprising the steps of:
longitudinally advancing a web having pressure sensitive
adhesive on a first side thereof; providing a supply of
liner/tab strip; advancing the liner/tab strip from the
supply laterally across the longitudinally advancing web
adjacent the first, adhesive bearing side thereof; cutting
the liner/tab strip to a length approximating the lateral
width of the web; urging a leading lateral edge portion of
the cut liner/tab strip against the first adhesive bearing
side of the advancing web to cause its adherence thereto;
and urging the remainder of the cut liner/tab strip against
the advancing web as the web carries the liner/tab strip
away longitudinally.
According to another aspect of the present
invention, there is provided an apparatus for applying a
laterally disposed liner/tab strip to an adhesive-bearing
side of a longitudinally moving web comprises: a supply of
liner/tab material; a cutter for the liner/tab material; a
roller drive for advancing the liner/tab material to the
cutter; a conveyor for advancing a cut section of the liner
tab/material severed by the cutter from the cutter to a
position aligned laterally across the longitudinally moving
web and spaced from its adhesive-bearing side; and means for
urging the cut section of the liner/tab material against the
adhesive-bearing side of the longitudinally moving web.
According to still another aspect of the present
invention, there is provided a process for sequentially
forming a plurality of coreless rolls of pressure sensitive
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adhesive tape comprising the steps of: longitudinally
advancing a web having first and second major surfaces, one
major surface thereof bearing pressure sensitive adhesive
thereon; applying a liner/tab across a lateral width of the
advancing web on the adhesive-bearing surface thereof;
winding the advancing web about a mandrel member to define a
tape roll, whereby an innermost wrap of the web for each
tape roll includes and extent of the liner/tab sufficient to
mask any exposed adhesive; and cutting the loner/tab and web
laterally into two segments, a first segment of the
liner/tab defining said extent for one tape roll, and a
second segment of the liner/tab defining a mask for adhesive
along at an outermost end portion of a web for a previously
wound tape roll.
According to yet another aspect of the present
invention, there is provided a liner/tab for masking the
trailing edge of a first roll of pressure sensitive adhesive
tape and the leading edge of a second, successively formed
roll of pressure sensitive adhesive tape, the liner/tab
comprising: a single masking sheet adhered to the adhesive
side of a length of pressure sensitive tape prior to winding
the tape upon itself, with the tape and sheet adhered
thereto being laterally severed into first and second
separate segments, with that portion of the sheet on the
first segment defining a mask for the outermost end of a
first roll of tape and that portion of the sheet on the
second segment defining a mask for the first wrap of a
second, separate roll of tape.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be further explained
with reference to the drawing figures referenced below,
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wherein like structure is referred to by like numerals
throughout the several views.
FIG. 1 is a schematic illustration of a tape roll
winding apparatus of the present invention.
FIG. 2 is a perspective illustration of a
completed tape roll formed by the tape roll winding
apparatus and method of the present invention.
FIG. 3 is an elevational view as taken generally
along lines 3-3 in FIG. 1.
FIGS. 4a and 4b are side elevational views, as
taken along line 4-4 in FIG. 3, with some parts removed and
some parts broken away.
FIGS. 5a and 5b are sectional views as taken along
line 5-5 in FIG. 3, with some components shown schematically
for illustrative purposes.
FIG. 6 is a schematic illustration of the tape
winding section of the tape roll winding apparatus of the
present invention showing the arrangement of components
configured for tape winding.
FIG. 7 is an elevational view of a winding mandrel
of the present invention, broken away laterally and with
portions thereof shown in section.
FIG. 8 is a perspective view of one end of the
winding mandrel of FIG. 7.
FIG. 9 is a sectional view as taken along line 9-9
in FIG. 7.
FIG. 10 is a sectional view as taken along line
10-10 in FIG. 7.
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FIG. 11 is an enlarged sectional view of the
encircled portion in FIG. 10, illustrating the
compressibility of the winding mandrel material upon which
tape is wound in the inventive method and apparatus.
FIG. 12 is an enlarged view of the encircled
portion in FIG. 7, illustrating axial removal of wound tape
rolls from the winding mandrel.
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FIG. 13 is a schematic illustration of the tape winding section of the tape
roll
winding apparatus of the present invention showing the arrangements of
components just
prior to severing of the advancing tape strips to initiate the formation of
coreless tape rolls.
FIGS. 14a-141 are schematic views, partly in section and partly in elevation,
of the
enveloper assemblies used for severing the advancing tape strips and
initiating winding.
about the winding mandrel, in the apparatus and method of the present
invention.
FIG. 15 is a partial elevational view as taken along lines 15-15 in FIG. 14a.
While the above-identified drawing features set forth a preferred embodiment,
other
embodiments of the present invention are also contemplated, as noted in the
discussion.
This disclosure presents illustrative embodiments of the present invention by
way of
representation and not limitation. Numerous other modifications and
embodiments can be
devised by those skilled in the art which fall within the scope and spirit of
the principles of
this invention. The drawing figures have not been drawn to scale as it has
been necessary
to enlarge certain portions for clarity.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIlyiENTS
Introduction and Overview
FIG. 1 illustrates an apparatus for performing the tape roll production method
of
the present invention. Essentially, the process involves starting with a
relatively wide and
long roll of a pressure sensitive adhesive web, and processing that roll into
a plurality of
narrower and shorter rolls of pressure sensitive adhesive tape. One such small
roll of tape is
illustrated in FIG. 2, as tape roll 15.
A tape roll winding apparatus 20 for fomiing coreless adhesive tape rolls is
illustrated schematically in FIG. 1. The process begins at a web unwinding
station 22,
where a supply 25 of pressure sensitive adhesive sheet or web material 26 is
aligned to feed
web material 26 onto a travel path for the web materia126 through the tape
roll winding
apparatus 20. As shown, the supply 25 is in large roll form. For purposes of
this
disclosure, the terms "sheet" and "web" are deemed equivalent. The terms
"length" and
"longitudinal" are used in reference to the dimension of movement of the web
materia126
along the travel path, while the terms "width" and "lateral" are used to refer
to the
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dimension at right angles to the travel path of the web materia126. The
direction of the
web travel path is at right angles to the axes of the supply roll 25 and other
process rollers
shown in FIG. 1. The web material 26 may be formed from any suitable materials
such as paper,
plastic, filament tape, nonwoven material or foil, and has first and second
major surfaces. A
pressure sensitive adhesive (tacky) layer 27 is borne on one of those major
surfaces, while
the other major surface has release properties (e.g., it is non-adhesive or
nontacky). As is
typical, the supply roll 25 is wound with the adhesive side of the web
material facing
inwardly toward the axis of the roll and the non-adhesive side of the web
material facing
outwardly.
For processing, the web material 26 is unwound from supply roll 25 over a peel-
off
roIler 28 which is movable toward and away from the axis of the supply roll 25
in order to
maintain contact with the periphery ofthe supply roll 25 as it unwinds. The
non-adhesive
surface of the web material 26 is thus drawn over the peel-off roller 28
(which is an idler
roller) and then over idler positioning rollers 29, 30 and 31 to align the web
material 26 for
liner/tab application. As seen in FIG. 1, the adhesive surface of the web
material 26 is
drawn over and around idler rollers 30 and 31 (those rollers are release
coated rollers). In
an alternative embodiment, one or more of the "idler" rollers disclosed herein
may be driven
to aid in the unwinding and advance of the web material 26 through the tape
roll winding
apparatus 20.
The non-adhesive surface of the advancing web material 26 is then drawn over a
back-up idler roller 32 in a liner/tab application station 35. In the
liner/tab application
station 35, a liner/tab applicator 37 is selectively activated to apply a
liner/tab laterally
across the advancing web material 26. The liner/tab serves to mask certain
selected
portions of the adhesive layer 27 on the web material 26. From the liner/tab
application
station 35, the web material 26 advances to a splicing station 39, where a
splice table 40 is
pivotafly mounted to provide a surface for manually splicing successive rolls
of web
material together. Alternatively, an on-line or "flying splice" mechanism may
be provided
to connect successive rolls of web material together.
As it continues along the travel path the non-adhesive surface of the web
material
26 then passes over an idler positioning roller 42 and through an edge trim
station 43. Each
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lateral side edge of the advancing web material 26 (and liner/tab thereon) is
trimmed to
define a precise width for the web rnaterial 26 for further processing. From
the edge trim
station 43, trimmed web material 43 a along each side edge of the advancing
web material
26 is directed over an idler roller 44 and then to a collection mechanism 43b.
As is typical
in tape winding apparatus, the collection mechanism 43b may constitute a level
wind
collector for the material trimmed from each side of the advancing web
material 26.
The web material 26 is also advanced over idler roller 44, and then over idler
rollers
45 and 46. The non-adhesive surface of the web material 26 engages idler
roller 45, while
the adhesive surface of the web material 26 engages idler rollers 44 and 46,
both of which
are release-coated idler rollers. The adhesive side of the web material 26
then engages main
drive roller 47 (which is also a release-coated roller). The main drive roller
47 provides the
primary traction or pulling force for advancing the web material 26 from the
supply roll 25
through the tape roll winding apparatus 20.
From the main drive roller 47, the web material 26 continues on to a driven
and
grooved anvil roller 48 (with its non-adhesive side toward the roller 48), and
a slitting
station 49 thereon. The web material 26 is then slit by a plurality of
laterally disposed and
spaced knives acting in cooperation with the grooved anvil roller 48 to form a
plurality of
longitudinally extending tape strips 50 and 51 of web material (see FIG. 1).
Extending
laterally, alternate tape strips 50 and 51 are directed either to a first
upper tape winding
station 52 or to a second lower tape winding station 53, respectively.
At each winding station, the advancing tape strips are wound about a winding
mandrel. Thus, a plurality of tape rolls are formed simultaneously on the same
winding
mandrel. In the upper winding station 52, initial winding of the innermost
wrap of each
tape strip 50 on a winding mandrel 55 is facilitated by a cut-off and winding
assembly which
has an upper enveloper assembly 56 and an upper lay-on roller and knife
assembly 57.
Likewise, initial winding the innermost wrap of each tape strip 51 about a
winding mandrel
60 in the lower winding station 53 is facilitated by a cut-off and winding
assembly which
has a lower enveloper assembly 61 and a lower lay-on roller and knife assembly
62. The
enveloper and knife assemblies at each winding station are mounted to
selectively pivot
toward and away from their respective winding mandrels. The winding mandrel 55
is
mounted at its ends in a rotating upper turret assembly 65. The upper turret
assembly 65
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has opposed chucks for engaging each end of the winding mandrel 55 and
rotatably driving
the winding mandrel 55 when it has been advanced to the upper winding station
52. Five
positions or stations are defined about the upper turret assembly 65, through
which the
winding mandre155 cycles during tape roll production, including a winding
mandrel loading
position A, ready position B, winding position C (upper winding station 52),
transfer
position D and unloading position E. Likewise, a lower turret assembly 70 is
provided with
opposed chucks for engaging each end of the second winding mandrel 60 and
rotatably
driving the winding mandrel 60 when it has been advanced to lower winding
station 53.
The lower turret assembly 70 also has five positions or stations defined for
movement of
the winding mandrel 60 therethrough, including a winding mandrel loading
position A,
ready position B, winding position C (lower winding station 53), transfer
position D and
unloading position E.
After a plurality of tape strips have been simultaneously wound about their
respective winding mandrel to a desired tape roll length, each tape strip is
severed and the
winding of tape rolls is completed on one winding mandrel while the winding of
a new set
of tape rolls begins about a new winding mandrel in each winding station. This
severing is
achieved while the enveloper and knife assemblies are advanced against a
winding mandrel
in its winding station. Each winding mandrel carrying completely wound tape
rolls is then
removed from its respective turret assembly, and the tape rolls thereon are
removed from
the winding mandrel.
As described below, this invention presents a unique apparatus and method for
forming those tape rolls without the use of separate tape roll cores. The tape
rolls are
wound directly on the winding mandrels. To facilitate this, each
circumferential segment of
the winding mandrel that is aligned to accept an advancing tape strip has a
tape engaging
surface that, in a radial orientation, is compressible yet sufficiently stiff
to support the tape
as it is successively wound about the winding mandrel to form a tape roll.
Each
circumferential segment is also independently rotatable about the axis of the
winding =
mandrel, with such rotation controlled by a clutch mechanism. In addition, the
winding of
coreless tape rolls is enhanced by utilization of a portion of the liner/tab
which had been
applied to the web material at the liner/tab application station. That
liner/tab portion is
aligned to form the innermost wrap of each tape roll, thereby masking the
adhesive of the
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web material at its innermost wrap from the tape engaging surface on the
circumferential
segment of the winding mandrel. The tape engaging surface is sufficiently
pliant to pernut
ready axial removal of the completed tape rolls off of the winding mandrel.
A coreless roll of pressure sensitive adhesive tape 15 as formed by the
present
inventive process is illustrated in FIG. 2. This tape roll 15 is formed from a
single tape strip
of web material 26 whose width was defined at the slitting station 49. The
tape roll 15 has
no separate core. Starting with its leading or inner edge 71, the innermost
wrap 72 of tape
strip is covered on its adhesive (inner) side by an extent of the liner/tab
which had been
applied to the web material 26 at the liner/tab application station 35, thus
forming a liner 73
for the tape roll 15. At its trailing or outermost edge 74, a tape tab portion
75 of tape strip
is defined that has its adhesive masked. The adhesive is masked by a segment
76 of a
liner/tab that was applied to the web material 26 at tab application station
35. The
remainder of that particular liner/tab formed the liner for a subsequently
formed tape roll in
the tape roll winding apparatus 20. Likewise, a segment of the liner/tab which
defined the
liner 73 of tape roll 15 formed the tab portion adjacent the trailing edge of
a previously
wound tape roll in the tape roll winding apparatus 20. Preferably, the
liner/tab is provided
with visually perceptible indicia 77 on one or both sides thereof, and the
indicia 77 is visible
upon formation of a completed tape roll 15 (both on tape tab portion 75 and
innermost
wrap 72).
Specific details regarding the coreless adhesive tape roll winding process and
apparatus of the present invention are described below. It is contemplated
that the
invention will take alternative forms and formats, some of which are
specifically noted. For
example, the tape roll winding apparatus 20 illustrated in FIG. 1 advances the
web material
26 with its adhesive surface facing generally upwardly. It is understood that
in some
applications it may be desirable to align the web material 26 so that for the
most part, its
surface bearing the adhesive faces generally downwardly. The disclosed
orientation is not
meant to be l.imiting, but merely illustrative. Numerous other modifications
and
embodiments of the inventive apparatus and process fall within the scope and
spirit of the
principles ofthis invention, and can be devised by those skilled in the art.
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Liner/Tab Applicator
FIGS. 3-5 illustrate the liner/tab application station 35 in greater detail.
As seen in
FIG. 3, a supply roll 80 of liner/tab material is rotatably supported on a
spindle 81 adjacent one side edge of the travel path of the web material. In
FIGS. 4a and 4b, supply roll 80 has
been removed from spindle 81 to perniit illustration of other components of
the liner/tab
applicator 37.
In FIG. 3, idler rollers 31 and 32 are seen, as rotatably supported at their
ends by
frame panels 82 and 84 (the web material 26 is not shown in FIG. 3, for
clarity). The
spindle 81 is rotatably supported on a central frame bar 86 which extends
laterally over the
travel path of the web material. The central frame bar 86 has a pair of
downwardly
extending supports 87 adjacent its lateral end portions (see FIGS. 3 and 5a)
which are
rotatably mounted relative to the frame panels 82 and 84 along a common
lateral pivot axis
88. Other operative components of the liner/tab applicator 37 are also
supported by the
central frame bar 86. As seen in FIGS. 4a and 4b, an air brake 89 is mounted
on the spindle
81 to provide rotation resistance, and thereby prevent loose outer windings of
liner/tab
material 90 from fomiing as rotation of the supply roll 80 is suddenly started
and stopped.
In addition, side spool screens or panels (not shown) may also be provided to
maintain the
liner/tab material 90 in proper alignment on the supply roll 80.
The supply roll 80 supplies liner/tab material 90 to a feed assembly 92, a
cutting
assembly 94 and a belt feed assembly 96. The liner/tab materia190 is drawn
from the
supply roll 80 and fed laterally relative to the travel path of the web
material 26 (facing its
pressure sensitive adhesive side) by the feed assembly 92. The feed assembly
92 includes
driven rubber-coated roller 98 and steel back-up idler roller 100, both of
which are
rotatably supported upon a roller support 102 mounted to the central frame bar
86. A drive
motor 104 operates via a gearbox 106 (see FIGS. 3, 4a and 4b) to drive chain
sprocket
108. Chain 110 engages driven sprocket 108 and, in turn, transmits power to
chain
sprocket 112, which is coupled via clutch 113 to a shaft 114 of driven roller
98. Activation
of motor 104 thus causes drive roller 98 (when clutch 113 is engaged) to
advance liner/tab
material 90 through the nip between rollers 98 and 100, and to feed the
liner/tab material 90 30 laterally across the cutting station 94 and into the
belt feed assembly 96.
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The cutting assembly 94 has a liner/tab knife 116, knife actuator 118 and
cutting
support table 120, all of which are supported from central frame bar 86 by
knife support
122 (see FIG. 3). Normally, the liner/tab knife 116 is retracted or spaced
above the knife
support table 120 sufficiently to allow liner/tab material 90 to pass
therebetween. Upon
activation of the knife actuator 118, the liner/tab knife 116 is driven down
through liner/tab
material 90, which is supported for cutting by cutting support table 120. The
cutting
support table 120 has a groove aligned under the liner/tab knife 116 for
permitting over
travel of the cutting knife 116 and to ensure complete cutting of the
liner/tab material 90.
The cutting assembly 94 thus severs the liner/tab material 90 into discrete
liner/tab
segments 123 for application to the web material 26.
The belt feed assembly 96 includes two laterally extending endless belts 124
and
126 which are aligned to have a longitudinal lateral belt run wherein the
belts 124 and 126
have contiguous and opposed outer faces. Upper belt 124 is supported at its
ends by belt
rollers 128 and 130. Lower belt 126 is supported at its ends by belt rollers
132 and 134.
The inner surface of each endless belt is grooved lengthwise, and the
circumferential
surfaces of the belt rollers have mating grooves and ridges to ensure that the
belts stay in
proper alignment during operation. The belt feed assembly 96 is also driven by
motor 104.
Power is provided via the gearbox 106 to a chain sprocket 136, and then
through chain 138
to chain sprocket 140. Chain sprocket 140 is, in turn, coupled to belt roller
132 to rotate
roller 132 and drive belt 126 mounted thereon. Consequently, belt 124, which
contacts belt
126 along their contiguous outer faces, is driven as well.
Belt rollers 132 and 134 for lower endless belt 126 are rotatably supported on
lower plate structure 142 (FIGS. 5a and 5b), which is, in turn, mounted to
bracket 144
secured to central frame bar 86. Belt rollers 128 and 130 for upper endless
belt 124 are
rotatably supported upon upper plate structure 146, which, in turn, is
pivotally mounted as
at lateral pivot axis 148 to a plurality of up-standing ear members 150,
which, in turn, are
secured to the bracket 144. Thus, the endless belts and their supporting
structure are all
supported by central frame bar 86, and when the central frame bar 86 is
pivoted about its
lateral pivot axis 88, the belt feed assembly 96 travels with it.
As seen in FIG. 5a, endless belts 124 and 126 are aligned with opposed facing
outer
surfaces 152 and 154. These surfaces are adapted to engage and entrain the
liner/tab
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material 90 therebetween, as it is readied for application to the web
materia126. The upper
and lower plate structures 146 and 142 also have opposed facing surfaces 158
and 160
which are aligned to retain the liner/tab segment 123 therebetween. The
opposing facing
surfaces 158 and 160 of the upper and lower plate structures 146 and 142 are
spaced apart
S sufficient to allow passage of the liner/tab material 90 therebetween. As
seen in FIGS. 5a
and 5b, the facing surfaces 158 and 160 of the upper and lower plate
structures 146 and
142 are recessed to accommodate the endless belts 124 and 126, as at recesses
166 and
167. The upper and lower plate structures 146 and 142 extend laterally across
the travel
path of the advancing web material 26 to a width at least the extent of the
width of idler
back-up roller 32. The upper and lower plate structures 146 and 142 are
designed to
separate. The upper plate structure 146 can pivot (as indicated by arrow 168))
about pivot
axis 148, and thereby pennit separation of the opposed facing outer surfaces
152 and 154
of endless belts 124 and 126. A plurality of laterally disposed spring
elements 169 are
positioned between the upper and lower plate structures 146 and 142 to
counteract the
weight of upper plate structure 146 during such separation.
Lay-on rollers 170 are rotatably supported on a plurality of ears 172 which
are
mounted to the upper plate structure 146. The lay-on rollers 170 are thus also
pivotally
mounted about pivot axis 148 relative to the central frame bar 86. The lay-on
rollers 170
are axially aligned laterally across the travel path of the advancing web
material 26, and
arranged to define a roller nip with idler back-up roller 32 for deposition of
the liner/tab
segment 123 on the advancing web material 26 (see FIG. 5b).
As mentioned, the central frame bar 86 and all components mounted thereto are
pivotally supported relative to the frame panels 82 and 84 about pivot axis
88. This
pivoting action (referenced by arrow 174) is attained by means of a three-
position, double-
acting pneumatic cylinder 176 having its cylinder portion 178 mounted to the
frame panel
84 by suitable means, such as mount bracket 180. An extensible piston rod 182
of the
cylinder 176 is pivotally connected at its outer end (as at pivot axis 183) to
an ann structure =
184 which, in turn, is mounted to one of the supports 87 for the central frame
bar 86.
Linear extension of the piston rod 182 relative to the cylinder portion 178
thus causes the
central frame bar 86 and components supported thereby to pivot about pivot
axis 88
(clockwise as viewed in FIGS. 4a and 4b, or counterclockwise as viewed in
FIGS. 5a and
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5b). When the piston rod 182 is in its most extended position (not shown), the
liner/tab
applicator 37 is pivoted away from the web path to allow alignment of the web
material on
the web path.
In operation, the liner/tab application station 35 applies a liner/tab segment
123
during advancement of the web materia126 along its travel path. Each liner/tab
segment
123 is aligned for lateral placement on the web material 26 as follows. Driven
roller 98 and
belt roller 132 are rotated by activation of the motor 104. The feed assembly
92 thus pulls
liner/tab material 90 from the supply roll 80, past the cutting assembly 94
and into the belt
feed assembly 96. A leading edge of the liner/tab segment 123 is engaged by
the opposed
outer surfaces 152 and 154 of the upper and lower endless belts 124 and 126
and liner/tab
segment 123 is then carried laterally across the travel path of the web
material 26. When
the leading edge of the liner/tab segment 123 is detected by an optical sensor
186, the knife
actuator 118 is signaled to drive the liner/tab knife 116 toward the cutting
support table 120
and thus cut and define a trailing edge of the liner/tab segment 123, while
also thereby
defining a leading edge of the liner/tab material 90 that will form the next
liner/tab segment.
Simultaneously, the clutch 113 is disengaged to stop rotation of the driven
roller 98 and
hence stop the advance of the leading edge of the liner/tab material 90 at the
cutting
assembly 94. The belt feed assembly 96 continues to operate, and continues to
laterally
advance the liner/tab segment 123 until its leading edge is detected by a
second optical
sensor 188. Upon detection of the leading edge by sensor 188, the motor 104 is
deactivated to stop the belt feed assembly 96. The endless belts 124 and 126
thus hold the
liner/tab segment 123 in position for application to the pressure sensitive
adhesive side of
the advancing web material 26.
The formation and positioning of a liner/tab segment 123 occurs while the
liner/tab
applicator 37 is in a ready or run position, as illustrated in FIGS. 4a and
5a. In this position,
the rod 182 of the cylinder 176 is extended to pivot the central frame bar 86
and the
components thereon about pivot axis 88 sufficient to space the liner/tab
segment 123 a
short distance away from the advancing web material 26, as best seen in FIG.
5a. A leading
lateral section 190 of the liner/tab segment 123 is, however, exposed below
lay-on rollers
170 and aligned to engage the adhesive surface 27 of the advancing web
material 26. This
engagement occurs when the cylinder 176 is activated to retract its rod 182
and pivot the
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central frame bar 86 and components thereon to move the liner/tab applicator
37 to an
applicator position, as shown in FIGS. 4b and 5b. In this position, the
leading lateral
section 190 of the liner/tab segment 123 engages the web material 26 and
adheres thereto.
The lay-on rollers 170 press and roll the liner/tab segrnent 123 against the
web material 26
as it is pulled out of the liner/tab applicator 37. A slight interference is
provided between
idler back-up roller 32 and lay-on rollers 170, which is accommodated by the
pivoting
about pivot axis 148 of the upper plate structure 146 and away from the lower
plate
structure 142 (see FIG. 5b). As mentioned, this movement and support of the
upper plate
structure 146 is facilitated by the springs 169 between the upper and lower
plate structures
146 and 142. This also separates the opposed outer surfaces 152 and 154 of the
endless
belts 124 and 126, thereby releasing the liner/tab segment 123 for its
withdrawal from the
liner/tab applicator 37.
After the second sensor 188 detects the absence of liner/tab material between
the
endless belts 124 and 126, the cylinder 176 is activated to extend rod 182 and
return the
central frame bar 86 and components thereon to the ready or run position
illustrated in
FIGS. 4a and 5a. The cylinder 176 is not activated to extend rod 182 solely in
response to
the detection of the absence of liner/tab material by the second sensor 188,
however. The
activation of cylinder 176 is also dependent upon completion of a
predetemiined time delay
in the circuit for retraction of rod 182 which initiated the application of
the liner/tab
segment 123 on the advancing web material 26. After the time delay and "no
liner tab
material" signal from the second sensor 188, the motor 104 is also activated
and clutch 113
engaged to initiate the steps necessary to position a next liner/tab segment
in position for
lateral application to the advancing web material 26.
The liner/tab applicator 37 of the present invention thus provides an
efficient supply
and delivery scheme for applying a mask onto an adhesive bearing side of a
moving web.
In this regard, the inventive liner/tab application scheme, although
illustrated in connection
with the formation of coreless pressure sensitive adhesive tape rolls, can
also be used in
connection with the formation of tape rolls having cores.
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Web Slitting Station
During operation of the tape roll winding apparatus 20, the web material 26
with
liner/tab segment 123 adhered thereto travels from the liner/tab application
station 35 to the
first lateral edge slitting station 43. At the first slitting station 43, a
pair of knives disposed
adjacent the lateral edges of the advancing web material 26 cut edge strips
off of the web
material 26 (and liner/tab segment 123 thereon) to define a precise width for
the web
material 26 for further processing. As mentioned, the material trimmed from
the web
material 26 is collected by a suitable collection mechanism 43b. As the web
material 26
passes the main drive roller 47, its progress is tracked by a length encoder
202 coupled to
the main drive roller 47. The length encoder 202 thus provides data as to the
extent of web
material 26 that has advanced along its travel path.
From the main drive roller 47, the web material is advanced to the anvil
roller 48,
which has a plurality of circumferential grooves extending side-by-side along
the width
thereof. The main drive roller 47 and anvil roller 48 are both driven by a
common drive
motor (not shown), as is conventional in tape slitting and winding machines of
this type.
The main drive roller 47 is driven to define line speed for the advancing web
material, while
the anvil roller 48 is driven slightly faster than drive roller 47.
While on the anvil roller 48, the web material 26 passes through the slitting
station
49, which operates in cooperation with the grooved anvil roller 48. The
slitting station 49
includes a plurality of knives 203 laterally disposed across the width of the
material web 26
travel path. Each knife 203 extends in part into one of the circumferential
grooves on the
anvil roller 48. Thus, as the web material 26 advances through the slitting
station 49, each
knife 203 cuts the web material longitudinally into a plurality of tape strips
50 and 51 (FIG.
6). The lateral space between adjacent knives 203 defines the width of the
tape strips cut
thereby, and preferably, the knives 203 are equally spaced apart.
As the tape strips 50 and 51 are slit in the slitting station 49, the
liner/tab segment
123 extending laterally across the web materia126 is also slit as it passes
the knives 203.
Thus, a liner/tab strip 204 is formed (as adhered to each tape strip 50), and
a liner/tab strip
205 is formed (as adhered to each tape strip 51) (see FIG. 13). From the anvil
roller 48, the
tape strips 50 and 51 are then directed to the upper and lower turret
assemblies 65 and 70.
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Alternate tape strips are directed to the alternative turret assemblies, as is
typical in a tape
slitter machine.
Coreless Tape Roll Winding
1. Turret Assemblies
From the anvil roller 48, the tape strips 50 are directed to the first winding
station
52 in the upper turret assembly 65. A winding mandrel 55a is rotatably driven
in the first
winding station 52, and the tape strips 50 are wound thereon, as seen in FIG.
6. Likewise,
the tape strips 51 are directed from the anvil roller 48 to be wound upon a
winding mandrel
60a rotatably driven in the second winding station 53 of lower turret assembly
70. Thus,
the tape strips 50 and 51 are simultaneously wound on separately rotating
winding
mandrels in their respective turret assemblies to form tape rolls 15 thereon.
The turret assemblies are preferably articulated turret assemblies, which are
of the
type which is conventional in the pressure-sensitive adhesive tape
manufacturing industry.
A suitable articulated turret assembly is the KampfRSA-450 turret of Jagenburg
GmbH,
Germany. In the articulated turret assemblies disclosed herein, each turret
assembly
consists of a pair of spaced turret heads 64 and 69 (only one of which is
shown in the
drawings for each turret assembly) between which the winding mandrels 55 and
60 are
supported and mounted for rotation, respectively. Conventionally, the turret
assemblies
contain drives (not shown) for indexing the turret heads, i.e., rotating them
to transport the
winding mandrels among different positions about each turret assembly. Each
turret
assembly has two or more pairs of winding mandrel chucks, and each pair of
chucks can
independently engage and independently rotatably drive a winding mandrel. It
is also
contemplated that a fixed turret assembly can be used for the present
invention, such as the
RS240 turret of Ghezzi & Annoni SpA, Italy.
A winding mandrel is positioned for use on its turret assembly by means of
loading
ramp 206. In articulated turret assemblies such as those illustrated and
contemplated for
use in connection with the present invention, each separate pair of winding
mandrel chucks
on a turret assembly has a separate drive motor to independently index those
chucks about
their positions on the turret assembly. A pair of empty chucks engage the ends
of the
winding mandrel at position A (off of the loading ramp 206). Those chucks are
then
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advanced to position B, placing the winding mandrel in a ready position for
tape winding.
The chucks are then further advanced to position C for engagement and winding
of tape
strips thereon. Once winding is nearly completed, that pair of chucks is then
indexed to
position D to finish the winding process for the winding mandrel therebetween.
Finally, the
chucks are advanced to position E, where the chucks release the winding
mandrel, thereby
allowing it to exit its turret assembly via unloading ramp 208. While the
relative positions
of the winding mandrel stations about the turret assemblies 65 and 70 differ,
their functional
aspects are the same, moving through winding mandrel loading position A,
winding
mandrel ready position B, winding mandrel winding position C (the winding
stations),
winding mandrel transfer position D and winding mandrel unloading position E.
All of the
winding mandrels in their respective chucks may be driven by one drive motor
through a
plurality of clutch means, or by separate independently controlled drive
motors, one for
each pair of winding mandrel chucks (these drive motors are not shown).
The unique structure of a caliper compensation winding mandrel of the present
invention is illustrated in FIGS. 7-12. For example, a winding mandrel 55 has
a central
cylindrical shaft 210 with ends 212 and 214. At least one end (such as end
212) has a
chuck engaging end portion 216, which is formed to mate with a chuck 218
having a
similarly shaped recess or mating portion 220 thereon. The end portion 216 may
be
squared off (as illustrated in FIG. 8), or it may have other rotational mating
structures such
as keyed portions or a tapered cone that operates in conjunction with a mating
shape on the
chuck. Adjacent the other end 214 of the cylindrical shaft 210, a chuck 222
also engages
the shaft 210. The chucks 218 and 222 are selectively movable axially away
from the shaft
210 to pemiit its loading and unloading on the upper turret assembly 65. When
engaged,
as seen in FIG. 7, however, the chucks 218 and 222 affirmatively engage the
cylindrical
shaft 210 for coupled rotation therewith.
An end stop sleeve 224 is secured to the cylindrical shaft 210 adjacent one
end
thereof. In one embodiment, the end stop sleeve 224 is fixedly secured to the
cylindrical
shaft 210 by means of pin 226, thereby limiting it from axial or rotational
movement relative
to the shaft 210. Alternatively, the position of the end stop sleeve 224 is
variable along the
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cylindrical shaft 210. A compression spring 228 is mounted about the shaft 210
adjacent
the end stop sleeve 224 and abuts an annular face end 230 of end stop sleeve
224, as seen
in FIGS. 7 and 8. A plurality of alternating spacer tubes 232 and core tubes
234 are aligned
along the length of the cylindrical shaft 210. One of the spacer tubes 232 is
positioned
adjacent the compression spring 228, with an annular face end 236 thereof
abutting the
compression spring 228. Each spacer tube 232 has an inner diameter slightly
larger than
the outer diameter of the cylindrical shaft 210. As best seen in FIG. 9, each
spacer tube
232 is aligned over a pin 238 extending through a bore 239 in the cylindrical
shaft 210.
Each spacer tube 232 has an axial groove 240 along its inner surface which
receives a head
242 of the pin 238 therein. Thus, the spacer tubes 232 can move axially
relative to the shaft
210, but the pin 238 prevents rotational movement of the spacer tube 232 with
respect to
the shaft 210.
A core tube 234 is aligned on the shaft 210 between each pair of adjacent
spacer
tubes 232, as seen in FIGS. 7 and 8, and is adapted for reusable use in
forming coreless
tape rolls thereon. Each core tube 234 is formed from a cylindrical sleeve 244
(see FIGS.
7, 10 and 11). Preferably, the sleeve 244 is formed from a low-friction,
durable material
such as DELRINTM material, available from E. I. du Pont de Nemours and
Company, Inc.,
of Wilmington, Delaware. The inner diameter of the sleeve 244 is slightly
larger than the
outer diameter of cylindrical shaft 210. The sleeve 244 is thus free to move
axially and
rotatably relative to the shaft 210, constrained only by means of the spacer
tubes 232.
A radially compressible material layer 246 is mounted about the circumference
of
each sleeve 244. Preferably, the material layer 246 is formed from
SCOTCHMATETM
hook material having a pressure sensitive adhesive backing, manufactured by
Minnesota
M'ming and Manufacturing Company of St. Paul, Minnesota, and identified by
Part No. 70-
0704-2795-3. As illustrated in FIG. 8, such material is preferably spirally
wound about and
affixed to the exterior circumferential surface of sleeve 244 by its adhesive
backing. This
SCOTCHMATETM material is defined by a base layer or fabric 247 which supports
a
plurality of upstanding stems 248. Each stem is formed as a small polymer
filament which
extends generally outwardly from the winding mandrel shaft 210 and has a hook
portion at
an outermost end thereof. While the radial orientation of the stems 248 is not
as uniform as
illustrated in FIGS. 7, 8 and 12, the outermost ends of the stems 248 of the
compressible
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material layer 246 are generally equal in height, and serve to define a low
surface area outer
circumference of the core tubes 234. It is about this outer circumference that
the tape strips
are applied and wound, and when the innermost wrap of each tape strip is
tightened
thereon, the compressible material layer 246 provides enough friction so there
is very little
or no slippage between the tape strips and the stems 248 during winding. The
tape strips
are applied directly onto the compressible material layer 246. When tape rolls
are formed
by the inventive method, as further discussed below, it is preferably not the
adhesive on the
tape strips 50 (or 51) which engages the compressible material layer 246, but
rather their
respective liner/tab strips 204 (or 205) which engage the compressible
material layer 246
and define an innermost wrap 72 of a tape roll 15 wound thereabout. As such,
the
innermost wrap 72 forms the liner 73 for the tape roll 15 (see FIG. 2).
As mentioned, the spacer tubes 232 and core tubes 234 alternate in the above-
described manner along the central cylindrical shaft 210. At the other end 214
of the
winding mandrel shaft 210, a second end stop sleeve 250 is secured over the
shaft 210 and
is secured thereto by pin 252. As seen in FIG. 7, an inner annular end face
254 of stop
sleeve 250 abuts an annular end face 256 of an adjacent core tube 234. The end
stops 224
and 250 are positioned on the winding mandrel shaft 210 to place the
compression spring
228 in compression, thereby placing an axial compression force against the
spacer and core
tubes 232 and 234. Thus, the core tubes 234, while free to rotate about the
shafft 210, are
retarded from completely free rotation by this arrangement. The amount of
rotation
inhibition is a function of a number of variables, including force exerted by
compression
spring 228, and serves to define a constant torque during tape winding.
As seen in FIG. 7, each core tube 234 is wide enough to accept a tape strip
for
fornvng tape roll 15. The spacing between core tubes 234 is determined by the
width of
the spacer tubes 232. However, because alternative tape strips are fed to the
winding
mandre155 from the anvil roller 48, the spacing between the edges of adjacent
tape strips
conzing to winding mandrel 55 is preferably the same as the width of each tape
strip (when
the knives 203 are equally spaced apart).
The winding mandrel illustrated in FIGS. 7-12 is a winding mandrel 55 for use
in
the upper turret assembly 65. As mentioned, the tape strips 51 being wound on
the
winding mandrel 60 in lower turret assembly 70 alternate (in lateral relation)
with the tape
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strips 50 being wound at the same time on the winding mandrel 55 in upper
turret assembly
65. With this in mind, it is understood that the winding mandrels used in the
upper turret
assembly 65 are functionally the same as the winding mandrels used in the
lower turret
assembly 70, except that the intervals of the spacer tubes and the core tubes
is reversed
along the lateral widths of the respective winding mandrels.
It is possible to manufacture tape rolls of different widths using the same
winding
mandrel (even at the same time). Such widths would be multiples of the
smallest possible
width (one tape roll per core tube). Thus, a tape roll could be formed on the
winding
mandrel that spanned two core tubes and a spacer tube therebetween (or three
core tubes
and the two spacer tubes therebetween, etc.) by revising the lateral spacing
of knives 203 in
the slitting station 49. Alternatively, different winding mandrels having
dffferent widths
(i.e., spacing) of their aligned spacer tubes and core tubes can be used with
correspondingly
different knife spacings in the slitting station 49.
Each winding mandrel thus serves as an axial base for tape winding. As a tape
strip
is advanced about the winding mandrel, it engages the compressible material
layer 246.
Specifically, when the tape is wound with its adhesive side facing the winding
mandrel
winding axis, the liner 73 (see FIGS. 2 and 11) engages the outermost ends of
the stems
248, since the liner 73 defines the innermost wrap 72 of each tape roll 15.
Collectively, the
stems 248 are stiff enough not to flatten as the innermost wrap 72 is placed
thereon, but
resilient enough to slightly bend and provide an overall diameter reduction
(radial
compression) as the innermost wrap 72 is tightened (i.e., cinched) about the
core tube 234
and then held in place by the adhesion of the further wraps of the tape strip
thereabout.
The stems 248 bend and allow a generally uniform compression about the core
tube 234,
thereby defining the inner diameter for each tape roll 15. The bending and
compression of
the stems 248 is illustrated in FIG. 12. A segment 257 of stems 248 under the
innermost
wrap 72 of a tape roll 15 is shown bent in compression about shaft 210. A
section 258 of
stems 248 on the same core tube 234 is shown uncompressed, where there is no
tape wound thereabout.
It is contemplated that other materials will also be suitable to define the
compressible and resilient material on the winding mandrel. Such materials may
include,
for example, a bristle structure such as BRUSHLONTM of Minnesota Mining and
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Manufacturing Company of St. Paul, Minnesota, or a loopy material having the
desired
resilience and compressibility characteristics. Other materials suitable for
this purpose
would include steel leaf springs, a plurality of spring-loaded devices such as
VLIERTM pins
(manufactured by Vlier Engineering, Burbank, California), steel VELCROTM
material
(manufactured by Velcro USA, Inc., Manchester, New Hampshire), a lubricous
foam
material, or some engineered composite of the above-mentioned materials, which
is a non-
exclusive list. Any such material is suitable, so long as it provides the
desired radial
compressibility, yet is stiff enough to maintain the tape material wound
thereabout for
defining its inner diameter and is low friction enough to perniit ready axial
removal of a
completed tape roll from the winding mandrel. The material is also
sufficiently resilient to
resume its original form after being compressed during the tape winding
process.
Preferably, the tensioner clutch mechanism for controlling the rate of
rotation of
core tubes (i.e., torque on the tape being wound) across a winding mandrel can
be
controlled by varying the compression of spring 228. To do so, the end stop
collar 224 can
be selectively fixed at adjustable positions along the shaft 210 (such as by
cooperative
threading between the collar 224 and shaft 210) or spacer shims can be added
between the
end stop collar 224 and spring 228 to vary the compression placed on the
spring 228.
Alternatively, instead of the spring 228, axial clutch pressure may be exerted
upon the
spacer tubes 232 by a yoke (supported adjacent the turret assembly) which
through
operation of a suitable activator, is moved to engage a radially disposed face
(such as face
236) of the outermost spacer tube on a winding mandrel and applies axial
pressure thereto
as the winding mandrel is rotated.
Another alternative winding mandrel tension construction has compressible
springs
adjacent each end of the winding mandrel (within fixed end stops on the
winding mandrel
shaft). A third fixed stop is secured to the shaft adjacent its midpoint, and
thus allows the
separate definition of axial compression (and torque) for each half of the
winding mandrel
by the two separately compressed springs.
It is also contemplated that a mechanically operable winding mandrel may also
function in the process and apparatus of the present invention. For example, a
diametrically
collapsible/expandable winding mandrel or button bar will suffice, so long as
it provides
caliper compensation (independent rotation capability for each tape roll being
wound) and
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means for support of the tape while wound and for permitting ready removal of
a
completed tape roll from the winding mandrel.
3. Cut-Off and WindingAssemblies
The initiation of coreless winding on a winding mandrel and the severing of
tapes
between successive winding mandrels in each turret assembly is facilitated by
a tape cut-off
and winding assembly that includes a pair of cooperative assemblies which
pivot into
engagement with the winding mandrel in its winding station. Thus, it is
imperative that the
turret assembly provide relatively precise positioning of the winding mandrel
in the winding
station so that it is properly aligned for interaction with the tape cut-off
and winding
assembly. As seen in FIGS. 6 and 13, for the winding station 52 of the upper
turret
assembly 65, the cut-off and winding assembly is defined by the upper
enveloper assembly
56 and the upper lay-on roller and knife assembly 57. The upper enveloper
assembly 56
includes an enveloper frame 264 supported by an arm 266 which is pivotally
mounted along
a lateral pivot axis 268. The upper knife assembly 57 has a knife frame 270
supported by
an arm 272, which is also aligned for pivoting along lateral pivotal axis 268.
Likewise, the
winding station 53 of the lower turret assembly 70 has a cut-off and winding
assembly
defined by the lower enveloper assembly 61 and a lower lay-on roller and knife
assembly
62. The lower enveloper assembly 61 has an enveloper frame 278 supported by an
arm
280 which is pivotally mounted along a lateral pivot axis 282. The lower knife
assembly 62
has a knife frame 284 supported by an ann 286 which is also pivotally mounted
along
lateral pivot axis 282.
Referring again to the turret assemblies (FIGS. 6 and 13), the wrapping of
tape
strips about a winding mandrel begins in its respective winding station, and
the bulk of the
winding also takes place in that winding station. When the winding of tape
strips 50 upon
winding mandrel 55a is nearly complete in the winding mandrel winding station
52 (position
C), an empty winding mandrel 55b is advanced by the upper turret assembly 65
into ready
position B (see FIG. 6). Likewise, the winding mandrel 60a is simultaneously
winding tape
strips 51 in its winding station 53 (position C) of the lower turret assembly
70. When the
winding on winding mandrel 60a is nearly complete, an empty winding mandrel
60b is
advanced to its ready position B.
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The enveloper and knife assemblies extend laterally to engage the winding
mandrel
and tape strips wound thereon in each winding station. During winding (as
illustrated in
FIG. 6), the enveloper and knife assemblies are pivoted away from their
respective winding
mandrels to permit the indexing of empty winding mandrels about the turret
assemblies
specifically (from position A to position B). However, when winding is nearly
complete
upon a winding mandrel (such as for winding mandrels 55a and 60a in FIG. 6),
the turret
assembly chucks in position C are indexed and winding mandrels 55a and 60a are
moved to
position D on their respective turret assemblies (as seen in FIG. 13). While
the winding
mandrels 55a and 60a in position D continue to rotate and wind tape strips
thereon, empty
winding mandrels 55b and 60b are moved from position B on each turret assembly
into the
winding stations (position C) for engagement with the advancing tape strips.
This winding
mandrel advance sequence is shown in FIGS. 6 and 13. As this winding mandrel
indexing
occurs, the enveloper and knife assemblies are pivoted toward each empty
winding mandrel
in its winding station. This pivoting is begun as a function of the amount of
web material
26 that has been advanced, as monitored by the length encoder 202.
In FIG. 13, the enveloper assemblies are shown to have advanced sufficiently
to
engage the tape strips advancing from the anvil roller 48 to the winding tape
rolls on
winding mandrels 55a and 60a, and the knife assemblies are ready to envelop
the winding
mandrel and advancing tape strips when the presence of a liner/tab strip on
the advancing
tape strips is detected. This is accomplished by means of optical sensors,
such as sensors
288 and 290 mounted on the enveloper assemblies 56 and 61, respectively. Thus,
for
example, when a leading edge of the liner/tab strip 204 is detected by the
sensor 288, the
upper enveloper and knife assemblies 56 and 57 are pivoted together to fully
envelope the
empty winding mandrel 55b and adjacent portions of advancing strips 50. The
sensor 290
operates in a similar manner to detect a leading edge of the liner/tab strip
205 for triggering
the final pivoting together of the lower enveloper and knife assemblies 61 and
62.
The sequence of tape cut-off and winding about a winding mandrel is
illustrated
specifically in FIGS. 14a-141. These figures and this discussion illustrate
the upper
enveloper and knife assemblies 56 and 57 and their operation. Other than
orientation, the
operation of the lower enveloper and knife assemblies 61 and 62 functionally
is the same, as
is the construction of those assemblies.
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The upper enveloper assembly 56 has a strand feed roller 292 and a cinch
roller 294
(FIG. 14a). The circumferential surface of the strand feed roller 292 is
defined by a
plurality of laterally spaced apart silicone rubber 0-rings 296. Likewise, the
circumferential
surface of the cinch roller 294 is defined by a plurality of laterally spaced
apart silicone
rubber 0-rings 298. The strand feed and cinch rollers 292 and 294 are
rotatably supported
from the enveloper frame 264 and are driven to rotate in an opposite direction
from the
rotation of the winding mandrel 55b. The strand feed and cinch rollers on each
enveloper
assembly are rotatably driven by a common motor (not shown) which is carried
by the
enveloper frame 264. As illustrated in FIGS. 14a and 15, a plurality of strand
guide fingers
300 are laterally spaced across the upper enveloper assembly 56. Each strand
guide finger
300 extends between adjacent 0-rings 296 on the strand feed roller 292, and
likewise
between adjacent 0-rings 298 on the cinch roller 294. Each strand feed guide
300 is
mounted at its base 302 to the enveloper frame 264, and has a first bridge
portion 303
between its base 302 and the strand feed roller 292, and a second bridge
portion 304
between the strand feed roller 292 and cinch roller 294 (see FIG. 15). Each
strand feed
guide 300 then has a distal finger portion 306 extending generally outwardly
from the cinch
roller 294. The distal portions of the strand feed guide 300 are shaped to
envelop the
empty winding mandrel 55b, as illustrated in Figure 14b.
A tail-winder assembly 308 is also carried upon the enveloper assembly 56. The
tail-winder assembly 308 includes an arm 310 pivotally mounted to the
enveloper frame
264 at pivot axis 312. An upper end of arm 310 is pivotally connected to a
linear actuator
314, such as a pneumatic cylinder which is pivotally mounter at its cylinder=
end to a support
316 fixed to the enveloper frame 264. An extensible rod 318 of the actuator
314 is
extended and pivotally coupled to an upper end of the arm 310 of the tail-
winder assembly
308. At its lower end, the ann 310 has a laterally extending anchor plate 320
which is
adapted to engage the tape strips 50. Lay-down rollers 322 are also pivotally
mounted to
the arm 310 adjacent its lower end, by a plurality of supports 324.
The upper lay-on roller and knife assembly 57 includes first and second lay-on
idler
rollers 326 and 328, which extend laterally across the tape strip travel path
and are release
coated. The second lay-on idler rollers 328 are rotatably mounted to knife
frame 270 by
supports 330. The first lay-on idler rollers 326 are rotatably supported by
support arms
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332, which are pivotally mounted to supports 330 as at lateral pivot axis 334.
The support
arms 332 and first lay-on idler rollers 326 are biased away from the knife
frame 270 by
suitable bias means such as springs 336.
A laterally extending tape knife blade 338 is mounted to the knife frame 270
adjacent the first lay-on idler rollers 326. A laterally extending tape tuck
plate 340 is
mounted adjacent the tape knife blade 338, between the tape knife blade 338
and first lay-
on idler rollers 326. A laterally extending tape pinning bar 342 is also
supported by the
knife frame 270 adjacent the tape knife blade 338. The tape pinning bar 342 is
biased away
from the knife frame 270 by suitable bias means such as springs 344.
4. Cut-Off and Winding Operations
FIG. 13 illustrates the upper enveloper and knife assemblies 56 and 57
immediately
prior to their complete envelopment of the empty winding mandrel 55b. This
relationship is
also shown in greater detail in FIG. 14b. During the operation of the cut-off
and winding
assembly, a plurality of tape strips can be simultaneously processed in
relation to a single
winding mandrel. For clarity of illustration, however, the following
discussion will relate to
the processing of a single tape strip.
Upon detection of a leading edge 350 of the liner/tab strip 204, the enveloper
and
knife assemblies 56 and 57 are pivoted together about the empty winding
mandrel 55b, as
illustrated in the sequence of FIGS. 14a-14e. In 14a, the enveloper assembly
56 and knife
assembly 57 are shown approaching the empty winding mandrel 55b, which
momentarily
contacts the advancing tape strip 50. In FIG. 14b, the enveloper assembly 56
is shown
contacting the rotating empty winding mandrel 55b, with its lay-down roller
322 (which is
release coated) engaging the advancing tape strip 50 to push it away from the
winding
mandre155b. This prevents the adhesive on the tape strip 50 from unnecessarily
running
over the compressible material layer 246 on the winding mandrel 55b. In FIG.
14c, the
enveloper assembly 56 and knife assembly 57 are shown first contacting tape
strip 50 for
tape cutting. Specifically, the adhesive side 27 of the tape strip 50 has
contacted and
adhered to the anchor plate 320 of the arm 310 on enveloper assembly 56, and
the tape
strip 50 is contacted on its opposite side by the tape pinning bar 342 of the
knife assembly
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57. At the same time, the first lay-on idler roller 326 engages the tape strip
50 opposite the
rotating winding mandrel 55b.
As the enveloper and knife assemblies 56 and 57 continue to merge together
about
the winding mandrel 55b, the springs 336 and 344 exert pressure against the
first lay-on
idler roller 326 and tape pinning bar 342, respectively. This secures a
segment 352 of the
tape strip 50 therebetween for cutting. As seen in FIGS. 14c and 14d, the tape
strip
segment 352 (bearing a leading part of the liner/tab segment 204 thereon) is
held in tension
as the tape knife blade 338 engages it. As seen in FIG. 14e, when the
enveloper assembly
and knife assembly 56 and 57 are fully coupled to envelop the winding mandrel
55b, the
tape knife blade 338 has severed the segment 352 of the tape strip 50. The
springs 336 are
in compression, urging the first lay-on idler rollers 326 against the winding
mandrel 55b.
The springs 344 are also in compression, urging the tape pinning bar 342
against the anchor
plate 320. The tape strip 50 is now defined as two tape strips 50a and 50b
(FIG. 14e),
where tape strip 50a is almost fully wound about winding mandrel 55a, and tape
strip 50b is
just beginning to be wound about winding mandrel 55b.
During this severing process, the anchor plate 320 and tape pinning bar 342
cooperate to secure an adhesive bearing portion of the tape strip 50a just
ahead of the
liner/tab strip 204. Thus, when the tape knife blade 338 severs the liner/tab
strip 204, it
defines, on the one hand, a segment 76 of the liner/tab strip 204 at the
trailing end of the
tape strip 50a which is being wound onto the winding mandrel 55a. Referring
again to
FIG. 2, this segment 76 masks the adhesive at the trailing end of the tape
strip, thereby
defining a tape tab portion 75. The remainder of the liner/tab strip 204 is
wound about the
winding mandrel 55b to form the innermost wrap 72 of a next tape roll 15 to be
formed,
and constitutes its liner 73 (FIG. 2). Further, the cutting defines the
leading edge 71 of the
innermost wrap 72 that will be defined by the liner 73, which is being
directed about the
winding mandrel 55b.
At all times while the tape strip 50a is held between the anchor plate 320 and
tape
pinning bar 342 (e.g., FIGS. 14c-14h), the first winding mandrel 55a continues
to rotate,
thereby placing the tape strip 50a between the tape roll 15 and the enveloper
and knife
assemblies 56 and 57 in tension. The winding mandrel 55a in FIGS. 14a-14k is
in position
D on the upper turret assembly 65, and while the winding mandrel shaft 210 of
the winding
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mandrel 55a in this position continues to rotate, the core tube 234 about
which the tape roll
15 is wound slips rotatably on the shaft 210 of the winding mandrel 55a to
hold the tape
roll 15 in the position illustrated by Figures 14c-14h.
The actual winding of the innermost wrap of a tape roll about winding mandrel
55b
is illustrated in the sequence of FIGS. 14d-14g. As seen in FIG. 14e, the tape
tuck plate
340 urges the just-severed leading end of the next tape roll to be formed
(edge 71)
upwardly toward the nip defined by the winding mandrel 55b and the 0-rings 296
on the
strand feed roller 292. The first bridge portion 303 of the strand feed guide
300 also aids in
directing that leading end into that nip. In FIG. 14f, the leading edge 71 is
seen in the nip
between the winding mandrel 55b and 0-rings 296 of strand feed roller 292. The
second
bridge portion 304 of the strand feed guide 300 aids in feeding the leading
edge 71 into the
nip between the winding mandrel 55b and 0-rings 298 of the cinch roller 294.
In FIG. 14g,
the leading edge 71 has now passed through the nip between the winding mandrel
55b and
the 0-rings 298 of the cinch roller 294. The distal finger portion 306 of the
strand feed
guide 300 aids in guiding the leading edge 71 into an underlying relationship
to the trailing
portion of the innermost wrap (liner 73) and the adhesive side of the tape
strip 50b
following it. The second lay-on roller 328 is aligned to urge the tape strip
50b into the
largest possible contact arc about the winding mandre155b, thereby defining
the overlap of
advancing tape strip 50b onto the innermost wrap as close as possible to the
distal finger
portion 306. Finally, in FIG. 14h, the leading edge 71 is seen as now over
wrapped by the
trailing end of the innermost wrap (formed by the liner 73). As the winding
continues, the
adhesive side 27 of the tape strip 50b contacts the liner 73 and is urged
against it by the first
lay-on idler roller 326 (which, although it has been pushed toward the knife
frame 270,
continues to be freely rotatable) to adhere thereto and secure the innermost
wrap diameter
about the winding mandrel 55b.
To facilitate the feeding of the leading end 71 of the liner 73 about the
winding
mandrel 55b and into the path defined by the strand feed guide 300 thereabout,
in one
alternative the first lay-on idler rollers 326 are driven at a rate faster
than line speed and
faster than the rate of rotation of the winding mandrel 55b. This tends to
direct the leading
end 71 away from the driven lay-on rollers 326 and up toward the travel path
defined by
the strand feed guide 300 about the rotating winding mandrel 55b.
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The strand feed and cinch rollers 292 and 294 are driven to rotate at a much
faster
circumferential speed than the line speed and rate of rotation of winding
mandrel 55b.
Thus, when the liner 73 engages the strand feed and cinch rollers 292 and 294,
it is forced
under increased tension into the nip between those rollers and the winding
mandrel 55b and
pulled relative to the line speed of the tape strip 50b. The increased rate of
rotation of the
strand feed and cinch rollers 292 and 294 also tends to direct the leading end
71 away from
the strand feed and cinch rollers 292 and 294, about the winding mandrel 55b
and under the
trailing edge of the liner 73. The strand feed roller 292 is driven via a one-
way clutch to
allow over-rotation caused by the cinch roller 294.
The increased tension placed on the innermost wrap (liner 73) as it is wound
about
the core tube 234 compresses the material layer 246 (via bending of stems 248,
as seen in
FIGS. 11 and 12), thereby defining the inner diameter of the innermost wrap.
The material
layer 246 is compressible under shear applied tangentially to its outer
surface (stems 248)
by the innermost wrap of tape as it is wound about the winding mandrel 55b in
tension.
The innermost wrap is thus pulled or cinched in tension about the winding
mandrel 55b to a
desired position, and this tension is held and maintained when the adhesive on
the tape strip
50b is wrapped about and secures the innermost wrap in place (preferably, the
length of the
liner 73 is slightly longer than the circumference of the cinched innermost
wrap). The
action of the strand feed rollers 292 and cinch rollers 294 and the winding
mandrel 55b
cause the innermost wrap to tighten about the winding mandrel 55b for a short
time. As
soon as the adhesive 27 on the advancing tape strip 50b contacts the wound
liner 73, the
increased pulling ceases, forming an interference fit of tape strip 50b around
the winding
mandrel 55b. The core tube 234 may rotatably slip relative to the winding
mandrel shaft
210 during this process. The end result is a relatively tightly wound
innermost wrap of the
tape strip, and specifically the leading portion of the tape strip covered by
liner/tab material
(liner 73), with successive windings of adhesive-bearing tape strip thereon.
During further
processing, the tape roll 15 does not slip rotatably relative to the core tube
234, but the
core tube 234 may slip rotatably relative to the winding mandrel shaft 210
(and indeed, is
designed to do so).
After the initial wrap of tape strip 50b around the winding mandrel 55b is
completed (FIG. 14h), the enveloper assembly 56 and knife assembly 57 pivot
about pivot
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axis 268 to separate and disengage from the winding mandrel 55b. As seen in
FIG. 14i,
once the enveloper and knife assemblies 56 and 57 are sufficiently separated
to disengage
the anchor plate 320 and tape pinning bar 342, the tension placed on the tape
strip 50a by
rotation of winding mandrel 55a pulls on the arm 310. The arm 310 is free to
pivot about
pivot axis 312, and thus pivots toward winding mandrel 55a, while rod 318
retracts into
cylinder 314. The tape strip 50a leading to winding mandrel 55a remains
adhered to the
anchor plate 320 initially, as illustrated in FIG. 14i. The winding mandrel
55a continues to
rotate, and because the tape strip 50a is no longer held to the enveloper
assembly 56, the
remainder of tape strip 50a starts winding onto tape roll 15 on winding
mandrel 55a and
pulling arm 310 toward winding mandre155a. Thus, the rotational slippage of
core tube
234 under the tape roll 15 on winding mandrel 55a slows as the tape roll 15 on
the winding
mandrel 55a again begins to rotate with the winding mandre155a. Eventually,
the angular
orientation of the anchor plate 320 and remaining strand of tape strip 50a
causes the
adhesive side 27 of the tape strip 50 to peel off of the anchor plate 320, as
illustrated in
FIG. 14j. Finally, the arm 310 is pulled to a position wherein the lay-down
roller 322
engages the outer circumferential surface of the tape roll 15 as it rotates,
thereby wiping or
rolling over the outermost layer thereof (FIG. 14k). The cylinder 314 holds it
in this
position momentarily and is then actuated to extend rod 318 and pivot arm 310
back in
place on the enveloper frame 264. The enveloper assembly 56 may dwell
momentarily on
the winding mandrel 55b as the arm 310 is pivoted out and back (as shown), or
the arm
310 may move during the pivoting away of the enveloper assembly 56 from the
winding
mandrel 55b.
The enveloper and knife assemblies 56 and 57 continue pivoting away from
winding mandrel 55b until fully retracted from the winding mandrel path
defined by the
upper turret assembly 65. At the same time, the rate of rotation of the
winding mandrel
55b is accelerated to achieve rapid winding of the tape strips 50b thereon.
The winding
mandre155b is rotated at a rate faster than the line speed of the advancing
web material 26.
Thus, winding mandrel rotation places the tape strip 55b under tension during
winding,
although less tension than placed on the tape strip 55b by the enveloper
assembly 56 during
initial wrap winding. The torque applied to each of the caliper compensating
core tubes
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234 is constant, as moderated by the force of compression spring 228 on the
independently
rotatable core tubes 234.
FIG. 141 illustrates a winding mandrel stabilizing assembly 354 which is
carried on
the upper knife assembly 57. The winding mandrel stabilizer assembly 354 is
not shown in
the other drawing figures for clarity. The winding mandrel stabilizer assembly
354 includes
a stabilizer finger 355 which is pivotally mounted, as at lateral pivot axis
356, to the knife
assembly 57. At its lower end 357, the stabilizer finger 355 is pivotally
coupled to an
extensible rod 358 of a linear actuator 359. The linear actuator 359 has a
cylinder portion
360 which is in turn pivotally mounted to the knife frame 270 by a support
361. An upper
end 362 of the stabilizer finger 355 is formed with a socket 363 adapted to
engage one of
the spacer tubes 232, preferably adjacent the midpoint of the rotating winding
mandre155b.
The lateral width of the stabilizer finger 355 is less than a width of the
tape strips 50b being
wound upon the winding mandre155b, wluch allows the stabilizer finger 355 to
extend
between adjacent tape strips 50b being wound on the winding mandrel 55b. One
or more
stabilizer fingers 355 may be provided along the winding mandrel, depending on
the width
and rotational rigidity of the winding mandrel.
At the desired high rate of rotation for winding mandrel 55b during tape
winding,
the stabilizer finger 3 55 acts to prevent undesired oscillation of the
rotating winding
mandrel 55b between its chucks. The actuator 359 is normally positioned with
its arm
retracted, so the stabilizer finger 355 assumes a position such as shown in
phantom in FIG.
141. Upon withdrawal of the upper enveloper assembly 56 from adjacent the
winding
mandrel 55b (after the innermost wrap has been formed and secured), the linear
actuator
359 is activated to extend rod 358 and thus pivot the stabilizer finger 355
into engagement
with the rotating winding mandre155b, as seen in FIG. 141. When a tape roll 15
is nearly
completely wound on winding mandrel 55b (an "in-process" tape roll), and the
winding
mandrel 55b is indexed to its next position D on the upper turret assembly 65,
the stabilizer
finger 355 is withdrawn to allow the indexing of an empty winding mandrel from
its ready
position B into the winding position C.
During winding of the tape strip on winding mandrel 55b, the tape winding and
cutting components resume the relative orientation illustrated in FIG. 6.
After the
enveloper assembly 56 has returned to its position illustrated in FIG. 6, an
empty winding
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mandrel in position A is then indexed to the ready position B to begin the
sequence anew.
The strand feed and cinch rollers are not driven when the enveloper assembly
56 is in its
ready position of FIG. 6. However, as soon as the enveloper assembly 56 begins
pivoting
toward the winding mandrel 55b, the drive motor borne thereon for the strand
feed and
cinch rollers is activated. Likewise, that motor is deactivated as soon as the
enveloper
assembly starts pivoting away from the winding mandrel 55b.
The winding mandrel 55a, now bearing a plurality of completed tape rolls 15,
is no
longer rotatably driven, and its chucks are indexed from transfer position D
to unload
position E on the upper turret of assembly 65. After a winding mandrel has
been removed
from the chucks of its turret assembly, with completed tape rolls 15 thereon,
the tape rolls
are extracted from the winding mandrel by sliding them axially along the
winding mandrel
(as in directions of arrows 365 in FIG. 12). The pliant stems 248 bend to
permit axial
movement of the tape roll 15 relative to the winding mandrel shaft 210, and
then after the
tape roll 15 has passed, the stems resume their original upstanding position
(as illustrated by
section 258 of stems 248 in FIG. 12).
The sequence of events illustrated in FIGS. 14a-141 happens quite quickly. The
advance of the tape strip 50 is not stopped to perform the cutting and initial
winding
operations illustrated in FIGS. 14a-141. The advance of the tape strip 50 is
slowed to a
speed lower than its winding speed, but it is not necessary to completely stop
and then
restart the tape strip advance.
Process Control
As described above, there are numerous motors and actuators which must be
precisely controlled to achieve the desired coreless tape roll winding. System
control is
preferably achieved through use of a microprocessor, which is operatively
coupled to the
various motors to control their actuation and speeds, and to the various
activators to
control their manipulation. For example, in the tab applicator 37, the
processor will actuate
the motor 104 based upon signals received from the optical sensors 186 and
188.
Likewise, the knife actuator 118 in the tab applicator 37 is activated based
upon signals
received from the processor by the optical sensors 186, 188, as is the clutch
113, and also
the operation of hydraulic cylinder 176. Similarly, the processor controls the
motor for
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advancing the web material through the apparatus, the motors for the turret
assemblies, the
motors for rotating the winding mandrels and the motors on the enveloper
assemblies. In
addition to the sensors and length encoder mentioned, it will be understood by
those skilled
in the art that further sensors may be provided as is typical to control the
operation and
coordination of such assemblies in a system of this type and complexity.
Example
In one embodiment of the present invention, a supply roll of web material is
provided with a nominal width of 60 inches. The tape is formed from a starting
supply roll
material of box sealing tape, TARTAN brand No. 371, having a thickness of .002
inch,
manufactured by Minnesota Mining and Manufacturing Company of St. Paul,
Minnesota.
After processing through an apparatus such as illustrated herein, 31 tape
rolls are formed,
and each finished tape roll is 48 mm wide and bears approximately 100 meters
of tape. The
finished tape roll has an inner diameter of 25 mm and an outer diameter of
about 3.25
inches. The line speed for tape winding (e.g., FIG. 6) may be, for example,
500 feet per
minute, with a slowdown for cut-off and the start of winding at about 3 feet
per minute.
During winding, the winding mandrel is rotated at a 5-10% faster rate than the
web material
advance speed. In addition, the winding mandrel rotation rate during winding
varies
depending upon the outer diameter of the tape roll wound on the winding
mandrel, as
controlled by the processor, in order to slightly exceed the web speed. That
diameter is
dependent upon the thickness of the web material and the tension placed
thereon during
winding. Initial web tension (at the start of the winding sequence for a tape
roll) is 2/3 to
3/41b/lineal inch width, and the tape rolls are wound in a constant torque
mode on the
winding mandrel. In this example, the core tubes on the winding mandrels were
covered
with SCOTCEVIATETM pressure sensitive backing hook material, manufactured by
Minnesota Mining and Manufacturing Company of St. Paul, Minnesota, Part No. 70-
0704-
2795-3, and each DELRIlN''M core tube had an outer diameter of.875 inches. The
strand
feed and cinch rollers were rotated, during winding of the innermost wrap, at
3-5 times the
web material advance speed. In making the tape rolls of this example, the tape
has a single
adhesive side and is wound with its adhesive side facing the winding mandrel
axis. A paper
liner/tab having a thickness of .003 inch and a length along the travel path
of the web
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material of 3.75 inches is provided. Once severed, approximately 3.25 inches
of the
liner/tab de$nes the liner for the tape roll, while the remainder of the
liner/tab defines the
tape tab portion at the outermost end of a previously formed tape roll.
Although the present invention has been described with reference to preferred
embodiments, workers skilled in the art will recognize that changes may be
made in form
and detail without departing from the spirit and scope of the invention. Thus,
the scope of
the present invention should not be limited to the apparatus and procedures
described
herein, but rather by the apparatus and methods described by the language of
the claims,
and their equivalents.
For example, the compressible and pliant material layer on the core tubes of
the
winding mandrel may also be used to facilitate the formation of a coreless
roll of pressure
sensitive adhesive tape using a level winding technique, rather than a
concentric winding
technique. In this instance, the adhesive liner on the tape strip being wound
is sufficiently
long to mask adhesive on the first pass of the level winding process, which
defines the
innermost spiral wrap on the tape roll ultimately formed thereby.
It is also contemplated that tape rolls be formed with no tape tab portion. In
this
instance, the cut-off and winding assembly is controlled to sever the
advancing tape strip at
the leading lateral edge of the liner/tab, thereby plaoing no liner/tab
material on the trailing
edge of the severed tape strip which is ultimately wound as the outermost wrap
and edge of
a finished tape roll. Thus, all of the liner/tab is used to form the liner of
the tape roll being
wound on the winding mandrel.
In another embodiment, a small lateral strip of the leading edge of a tape
roll being
wound on the winding mandrel is bent back upon itself as it is wound around
the winding
mandrel. As that bent-over lateral strip is wound about the winding mandrel,
it then first
engages the adhesive of the advancing tape strip. Thus, the leading edge
itself is not
exposed, but rather sandwiched and secured between the first and second
innermost wraps
of the tape roll being formed. This arrangement thus reduces the possibility
that an
underlapping portion of the leading edge is unadhered and thus prone to catch
and become
inadvertently peeled from the tape roll.
Although discussed primarily above in the context of pressure sensitive tape
having
adhesive on one side thereof, with the adhesive being wound on the inner side
of the tape
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windings, it is contemplated that the inventions defined herein are applicable
to form
coreless rolls of tape wound in an opposite configuration (with the adhesive
side facing
out), as well as to form coreless rolls of pressure sensitive adhesive tape
transfer materials
and double-sided pressure adhesive tape. It is understood that the winding of
coreless tape
rolls with the adhesive side facing away from the winding mandrel winding axis
will result
in some different process considerations. For instance, when a liner is
provided which
masks the adhesive on the innermost wrap of such tape, the adhesive on the
tape will not
engage successive windings thereof until the initiation of the third wrap of
tape about the
winding mandrel. Thus, it will be necessary to maintain the increased tension
on the tape as
it is wound for two initial wraps about the winding mandrel in order to cinch
the tape about
the winding mandrel using its own adhesive. In that regard, the roller and 0-
rings on the
cut-off and winding assembly must necessarily be release coated or formed of a
suitable
material (i.e., silicone rubber) because they will be contacting the adhesive
bearing side of
the tape. Because the adhesive is on an opposite side of the tape, the tail-
winder assembly
308 must be reconfigured, since there would be no adhesion of the severed tape
to the
anchor plate, but rather to the pinning bar 342. Further, because the
outermost wrap of a
finished tape roll would have its adhesive on its outer surface, the length of
the liner/tab
may be extended so that the segment thereof which previously formed the tape
tab portion
is long enough to extend about the entire outermost wrap of the finished tape
roll, thereby
masking exposed adhesive thereon. Pressure sensitive adhesive tape wound with
its
adhesive side out requires no liner on the innermost wrap to prevent adhesive
from
engaging the winding mandrel, since the non-adhesive side of the tape faces
the winding
mandrel. Thus, it is contemplated that no liner be provided for the innermost
wrap, in
which instance the adhesion by wrapping about the winding mandrel would begin
with the
second wrap. If a liner/tab is provided, the liner/tab may be severed at its
trailing lateral
edge by the cut-off and winding assembly and serve only to mask the outermost
wrap of a
finished tape roll, rather than as a liner for an innermost wrap.
